1. Field of the Invention
The present invention relates to a distance measurement apparatus and method by using a single cell sensor.
2. Description of the Related Art
In the related art, a time-of-flight (TOF) sensor including a plurality of cells has been used in order to recognize distances and the motion of objects in space. The TOF sensor senses light, emitted from an infrared ray (IR) light source and reflected and returned thereto. The TOF sensor is connected to a depth camera generating depth information to be used to calculate a distance to a specific object. The calculation of distance is carried out by two sensors generally including a plurality of cells. The two sensors are sequentially switched on and off, to thereby measure the distance to a specific object. However, the respective cells of two distance sensors comprise a pair, to thereby be complementarily controlled, which may lead to an increase in the sizes of the cells. In addition, a distance sensor including a plurality of cells may increase manufacturing costs and a product unit price, as compared with a distance sensor including a single cell.
Patent Document 1 of the following Related Art Documents is directed to a distance sensor, a three-dimensional image sensor, and a distance calculating method. According to Patent Document 1, the light source is periodically switched on and off to thereby periodically transmit light to a target object; the light reflected from the target object is received by a light detector; and the points in time at which the reflected fragments of light received by the light detector are detected are differentiated from each other according to a plurality of light detecting devices provided in the light detector, so that the distance to the target object is calculated by the maximum charge amount among the charge amounts detected based on different sensing points in time.
Patent Document 2 of the following Related Art Documents is directed to a gate type 3D camera determining a distance to a target object, and includes a light source including a series of pulses of light having a characteristic spectrum controlled to illuminate the target object; a photosensitive surface including a plurality of light detecting devices; an optical instrument visually displaying reflected light on the photosensitive surface; and a shutter operable to selectively switch the photosensitive surface for light in the spectrum on and off.
Patent Documents 1 and 2 of the Related Art Documents have an effect of decreasing the size of cells by using a single distance sensor, as compared with the related art. That is, the problem in which the size of cells is increased was solved. However, Patent Documents 1 and 2 of the Related Art Documents, which employ the distance sensor including a plurality of cells, did not solve the limitations of increasing manufacturing costs and manufacturing costs per unit as compared with the distance sensor including a single distance sensor.